Many web advertising sites use user profile information such as sex, age, marital status, education, and income to target online adverting to users. Some sites offer contextual advertising, where the ads are text or links that are relevant to the page that the user is accessing. For example, Gmail™ indexes email messages, and based on the message content adds text and links to related pages. Location-based contextual advertising can take contextual advertising one step further by targeting the ads to both context and the user's location.
Mobile devices such as smart-phones are information and communication devices that can generate text as well as multimedia content such as pictures, audio and video. There are situations when it is useful to know the exact time and location of the mobile when the content was generated. For instance, when users add pictures and video to their online albums, social networking sites (e.g. Facebook®, MySpace™, YouTube®, Twitter™ and Linkedln®), and other web sites they manually describe and label the data, time and location of the content. Likewise, servers that handle email, Short Message Service (SMS), and blog entries note the time they received the content, rather than the time the content was created by a client device. Geotagging, which is the process of adding geographical identification data to multimedia content, solves these problems by adding self-describing metadata to the content. Some photo sharing web sites support geotagging.
Other systems have used positioning technologies to provide location-based information and advertising. For instance, a wireless network with base stations has been used to locate a subscriber and use the location to filter responses to information requests. Also, cellular base stations have been used to locate a cellular phone user and provide location-specific information to travelers such as airline and traffic information. Other systems have utilized GPS to locate a user and provide advertising that takes into account the user's location and profile. A location-based content targeted online advertising system have been described where one of the factors that determines the content of the advertisement is the location of the user as determined by a location server. Others have described a location-based advertising system that uses a GPS-based polling method to locate the user.